This study characterized the chemical composition of hyphal walls from Penicillium rubrum Stoll, a toxigenic fungus that produces rubratoxin B, a hepatotoxic and teratogenic compound. Researchers grew P. rubrum cultures, isolated hyphal walls through mechanical disruption and washing, and analyzed their chemical components using various chromatographic and analytical techniques. The hyphal wall was composed primarily of carbohydrate (67.4%), with glucose as the major sugar (44.6%), followed by smaller amounts of hexosamines (15.4%), galactose (5.4%), and mannose (0.6%). Protein and lipid constituted 7.2% and 17.07% of the wall, respectively. Amino acid analysis identified 16 amino acids, with glutamic acid and leucine being predominant. Chitin was confirmed as a component of the wall. Mineral analysis revealed calcium, magnesium, potassium, manganese, and iron. The P. rubrum hyphal wall composition was generally comparable to other Penicillium species, though it contained relatively high lipid content. The research was designed as a preliminary investigation into whether the hyphal wall composition contributes to the fungus's resistance to its own rubratoxin B production.

Key findings

• P. rubrum hyphal walls consist of 67.4% carbohydrate (predominantly glucose at 44.6%), 17.07% lipid, and 7.2% protein, accounting for 96.5% of dry weight
• Glucosamine (component of chitin) represents 15.4% of the wall composition, with chitin confirmed by iodine testing and infrared spectroscopy
• Lipid content (17%) in P. rubrum walls is notably higher than other Penicillium species previously studied
• Sixteen amino acids detected in wall protein, with glutamic acid (9.9%) and leucine (11.3%) being most abundant
• Mineral components including calcium (0.57%), magnesium (0.45%), and trace elements comprise 5% of the wall ash